What is water energy?

Water is the most abundant substance on the surface of the planet. It’s in constant motion due to the actions of the sun and the moon. The sun drives the water evaporation cycle while the moon is largely responsible for the ocean tides. When we talk of water energy, we tend to think of using the mechanical energy in stored or moving water. Water also possesses kinetic energy (which is the energy possessed by moving masses) as well as thermal energy (which is energy pertaining to heat or temperature) when the water has been warmed by the sun or the earth.

The total energy generating potential of waves breaking on the world’s coastline is estimated to be about 2 to 3 million megawatts (MW), according to the U.S. Department of Energy . Renewable energy analysts believe there is enough energy in the ocean waves to provide up to two terawatts of electricity. A terawatt is equal to a trillion watts. Electricity can be generated from water energy, whether the source is ocean-based or river-based. Worldwide, water is the most commonly used renewable energy resource, providing enough power to meet the needs of 28.3 million customers. Ocean-based sources include wave energy, tidal energy and thermal energy. River sources are primarily hydro-electric schemes of varying sizes, many of them associated with irrigation or flood mitigation schemes. About 20 per cent of the world’s electricity is generated through the use of water, according to the Hydro Research Foundation.

A hydro-electric project operates at the Kariba Dam in Zimbabwe and it is one of the world’s largest dams. For more information, go to:
http://www.answers.com/topic/kariba-dam

However water is a very precious resource that is becoming scarcer in many parts of the world. For more information about global water scarcity, go to:
http://www.unesco.org/water

Another significant challenge is that the practical development of water energy is still relatively costly. A balanced mix of non-renewable and renewable energy sources is needed to supply our electricity needs in Australia. Hydro sources accounted for seven per cent of Australia’s electricity generation in 2004/2005, according to the Energy Supply Association of Australia.

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